1. Technical Field
The present invention relates generally to temporary stents for use in providing a temporary halt to blood flow in venal injury. More particularly, the present invention provides a temporary intravascular stent for use in retrohepatic IVC or hepatic vein injury which is capable of expanding to the appropriate size of a blood vessel without reducing preload.
2. Summary of Related Art
Historically, many severely injured persons have not benefitted from the facilities of the hospital emergency room because the severity of their injuries prohibited them from arriving on the surgical table in a timely manner. However, as prehospital care has improved, more severely injured patients have appeared in emergency rooms of hospitals within an appropriate time of the injury. Nevertheless, even in the improved environment of today's prehospital care, the nature of many injuries challenges even the best skills. For example, while injuries to the vessels lying behind the liver account for only about ten percent of overall liver trauma, such injury carries a grave prognosis. Only between fifty and fifty-five percent of these patients arrive at the hospital alive. Even out of this relatively small number, these patients demonstrate an astonishing mortality rate of between seventy and ninety-five percent. Sadly, little advancement has been made over the past twenty ears in the treatment of this type of injury which knows no age group and afflicts both children and adults.
An array of medical deices designed to address this type of problem have been developed. Such devices include the atriocaval shunt and the saphenofemoral balloon shut. In addition, different methods have been attempted in the resolution of such injury. Such methods include the venovenous bypass, total vascular occlusion of the liver, and transection of the supra hepatic vena cava.
The saphenofemoral balloon shunt provides several advantages to the other devices and methods in that it avoids an emergent thoracotomy while offering simplicity in its insertion. This type of device does, however, have some significant disadvantages. Specifically, the saphenofemoral balloon shut significantly decreases blood return to the heart, exact position of the balloon cannot be determined and the balloon may migrate causing vascular compromise to other organs. In addition, the exact position of the balloon cannot be determined at any given time.
The inventor of the present invention recognized that one possible solution to the above-described injury is the intravascular stent. A survey of known stents, however, reveals that there are no known stents which would lend themselves toward the effective resolution of the problem.
U.S. Pat. No. 5,151,105, issued Sep. 29, 1992 to Kwan-Gett, discloses an implantable collapsible tubular sleeve for use in a fluid vessel. The stent includes an inner body portion having an inner coiled wire spring. At each end of the stent is provided a pair of circular support members.
U.S. Pat. No. 5,282,824, issued on Feb. 1, 1994, to Gianturco, discloses a self-expanding stent assembly for use within a body passageway. The assembly includes a plurality of Z-shaped stents which are arranged to form an internal cage. An external nylon sleeve is fitted over the cage.
U.S. Pat. No. 5,344,444, issued Sep. 6, 1994, to Glastra, discloses an expandable cylinder formed from a hollow expandable ring or sleeve which may be inserted into a body vessel. With specific reference to FIG. 11, an expandable tube 40 includes an outer wall 42, an inner wall 44, and end walls 46 and 48.
U.S. Pat. No. 5,356,423, issued Oct. 18, 1994, to Tihon et al. discloses a resectable self-expanding stent having a fenestrated side wall. The stent includes a generally tubular member having a pair of opposed ends and a fenestrated wall surface.
U.S. Pat. No. 5,411,549, issued May 2, 1995, to Peters discloses a selectively expandable and retractable stent which may be rolled and unrolled. With particular reference to FIG. 5, the stent 10 includes a tubular section 12 (shown in FIGS. 1 through 3) and a rectangular body portion which is capable of being wrapped onto itself prior to insertion into the vessel.
U.S. Pat. No. 5,474,563, issued Dec. 12, 1995, to Myler et al. discloses a cardiovascular stent and a tool for its retrieval. The stent comprises a generally tubular body having a central lumen which extends between its proximal end and its distal end. An outer sheath is provided.
U.S. Pat. No. 5,634,941, issued Jun. 3, 1997, to Winston et al. discloses a graft bypass apparatus which is movable between a collapsed state for insertion to an expanded state in its operating position. The apparatus or stent is in the form of a thin sheet which is initially flat but which may be wound up tightly around a spool into a roll. The stent naturally tends to expand. An expandable tubular graft is fitted around the stents. The graft includes a plurality of pleats or folds.
U.S. Pat. No. 5,690,643, issued Nov. 25, 1997, to Wijay discloses a stent delivery system which comprises a movable inner tube and a fixed outer tube. The stent is of the expandable type and is expanded by movement of the inner tube which is axially manipulated with respect to the outer tube so that the undulations or bends effect expansion of the stent.
U.S. Pat. No. 5,730,698, issued Mar. 24, 1998, to Fischell et al. discloses a balloon expandable temporary radioisotope stent system. The system includes an angioplasty catheter and a stent. As illustrated best between FIGS. 1 and 5, a stent 31 is provided on a balloon angioplasty catheter 20. The distal end of the stent 31 is fixed to the distal section of the catheter 20 and the proximal end of the temporary stent 31 is fixed to a distal end of a pusher tube 32. The pusher tube 32 cooperates with the proximal section of the balloon angioplasty catheter 20 and allows the stent 31 to be reversibly deployed in a radially outward manner.
U.S. Pat. No. 5,735,869, issued Apr. 7, 1998, to Fernandez-Aceytuno discloses a balloon catheter and stent delivery device. The balloon catheter is intended for carrying a balloon expandable stent into a body vessel. The catheter includes a dilation balloon.
U.S. Pat. No. 5,800,522, issued Sep. 1, 1998, to Campbell et al. discloses a tube for insertion into a blood conduit and the like. The tube in the form of a liner is secured by the stent.
While representing developments in the art, known stents fail to provide a satisfactory temporary vascular stent having particular application in retrohepatic IVC or hepatic vein injury. Accordingly, advancements in the field remain wanting.